The present invention relates to flame retardant polymer systems and to polymerized compositions comprised of an interpolymer of a reaction product of a hexahalocyclopentadiene, a polyhydric alcohol, a polycarboxylic acid containing aliphatic carbon-to-carbon unsaturation, a styrene-type monomer, maleic acid or anhydride and a copolymerizable brominated comonomer, such as a brominated neopentyl acrylate.
The present polymer systems are useful in the preparation of articles of commerce fabricated of polyester resin polymers which are cast, molded or laminated. The present polymer systems are particularly adapted to the preparation of transparent or translucent laminates containing fillers, such as glass, used in the construction transport and other industries.
The standards of flame retardancy for such articles have steadily increased over the years in steadily increasing increments. This is presently accented by the increasing number of laws and regulations relating to flame retardant properties of polymers used in industry and especially those used in the construction industry. Many polymer compositions previously considered to be flame retardant and useful in industry do not meet the standards of today or the improved standards which are almost certain to be set in the future. Thus, flame retardant resin compositions developed at this point in time must not only meet today's standards but must meet higher standards to be viable in the marketplace. In addition to improved flame retardant standards, other properties, such as strength and transparency, are continuously improving, and a product, to be commercially competitive, must be as good as, or better than, the flame retardant polymer compositions available today. The present flame retardant systems and polymers fulfill these criteria.
The present invention relates to polymer systems, that is, polymerizable mixtures of components, and also to polymerized compositions of such systems in their finally reacted form as insoluble, infusible compositions.
It has previously been proposed to add materials with known flame retardant properties to polymer systems to increase flame retardancy of the system. However, many additives adversely affect the physical properties of the final polymer compositions, such as strength or transparency, or have a detrimental effect on the gelling or curing conditions of the polymer system. Further, obtaining a good distribution of dispersion of such additives through the polymer system is most difficult. The present interpolymerizable systems and polymerized compositions are characterized by good compatibility of reactable moieties having flame retardant properties throughout the mixture and by high strength obtained from interpolymerization of the components.
Polyester polymer systems and compositions containing adducts of hexahalocyclopentadiene are known in the art and are more fully described in U.S. Pat. Nos. 2,779,700 and 2,779,701, the teachings of which are hereby incorporated by reference.
Briefly, the hexahalocyclopentadiene component may be a chloro, bromo or fluoro substituted cyclopentadiene wherein all of the hydrogens are replaced by a halogen. Hexachlorocyclopentadiene is presently the most economic and readily available hexahalocyclopentadiene and, hence, is preferred in the present invention. The hexahalocyclopentadiene component is utilized in the form of an adduct which is capable of being esterified with a polyhydric alcohol or a polycarboxylic acid. More preferably, the adduct is the reaction product of hexachlorocyclopentadiene and maleic acid or anhydride to produce 1,4,5,6,7,7-hexachlorobicyclo-(2.2.1)-5-heptene-2,3-dicarboxylic acid or anhydride. Such compounds are sometimes referred to as chlorendic acid or anhydride and may be so referred to hereinafter in the present specification.
The polymer compositions of the present invention may be prepared by conventional mass or solution polymerization techniques.
The use of brominated neopentylacrylates in styrene or acrylonitride based resins to impart flame retardancy are disclosed in U.S. Pat. Nos. 3,480,600; 3,755,498; 3,763,644; 4,032,509; and 4,051,311. However, none of such patents teach the use of an interpolymer containing a reactive adduct of a hexahalocyclopentadiene which is characteristic of the present polymer systems compositions.